I found out about this company through TravelZoo.
We took the 3 hour, 1 PM tour and came almost 45 minutes prior as per instructions. After checking in, we ate lunch before boarding.
We did see dolphins on the trip, and, throughout, the captain helpfully told everyone over the PA in which direction to look to see dolphins or whatever else happened to be of general interest. They have other employees on the ship, too, one of whom was a marine biology student who was quite knowledgeable in his field and was friendly and answered our questions about the ecology, etc.
At one point, the captain maneuvered the boat in such a way so as to create waves of water which, he said, the dolphins like, and sure enough, they started jumping through it, which is when I took the attached photo. We also spotted them at other times, too, though they were more quick-out-and-in than they were when he made those waves.
The waters were quite calm, though the visibility happened to be generally hazy. But we did see dolphins, and it was a pleasant and enjoyable ride for the family.